JP6086517B2 - Electric field time grating angular displacement sensor - Google Patents

Description

The present invention relates to a precision angular displacement measurement sensor.

In recent years, in the field of precision angular displacement measurement sensors, time grating sensors using clock pulses as a reference for displacement measurement have been developed, and based on this, time grating angular displacement sensors based on alternating electric fields have also been developed. As this type of sensor, there is Chinese Patent Document CN102425987A, which was published on April 25, 2012, and whose title is “time grating angular displacement sensor based on alternating electric field”.

  A time grating angular displacement sensor based on an alternating electric field is used as a signal coupling path using a single layer structure differential capacitance, and a two-path standing wave signal is obtained by two annular electrodes. Composite to signal. However, due to the mismatch in the length and width of the two annular electrodes processed on the cylinder end face, the change rules of the corresponding standing wave signals of the two paths are different, and mutual interference between the two annular electrode signals can occur. Measurement errors increase, which hinders accuracy improvement. It is difficult to match the two annular electrodes in the manufacturing process, and it is difficult to match the electric field coupling strengths of the two annular electrodes even in the mounting operation. This causes a mismatch in the amplitudes of the standing wave signals in both paths, resulting in measurement errors. Therefore, adaptability to industrial sites was low.

An object of the present invention is to provide an electric field time grating angular displacement sensor based on a single circular multilayer structure that solves the above-described problems of the prior art. According to the present invention, by using an electrode having a single circular multilayer structure, the problem that signals between two annular electrodes interfere with each other and the length and width of the electrodes do not match is solved. The problem of causing a mismatch between the two annular electric field coupling strengths can be avoided. Further, since a traveling wave signal is directly obtained using the electric field coupling principle, it is not necessary to provide an adding circuit. Therefore, measurement errors can be reduced, required mounting accuracy can be reduced, and the system structure can be simplified.

The present invention is an electric field type time grating angular displacement sensor based on a single circular multilayer structure, which includes both a rotor and a stator, and the rotor substrate and the stator substrate are two types using a cylindrical body or a cylindrical ring. Can be realized.

A first method for realizing the sensor is to arrange electrodes along the upper and lower end surfaces of a cylindrical body or a cylindrical ring. Both the rotor substrate and the stator substrate use a cylindrical body or a cylindrical ring, and the lower surface of the rotor substrate (that is, the end surface of the cylinder) is a bisinusoidal shape (circumferentially) formed by two vertically sine curves. Rotor electrode of the shape after spreading along) is arranged, the number of rotor electrodes is m (m is an integer of 1 or more), it is uniformly arranged on the circumferential surface, and the rotor electrodes are connected by conducting wires Has been. The surface on the stator substrate (that is, the end face of the cylinder) is covered with four layers of dielectric films, the first layer is a metal film, and constitutes four excitation signal conductors. The second layer is an insulating film. The third layer is a metal film and constitutes a stator electrode, and its shape is a fan shape (that is, a shape extending along the circumferential direction), the size is the same, and between two adjacent electrodes The fixed insulation interval is maintained, the number of stator electrodes is 4 m, and they are uniformly arranged on the peripheral surface. The fourth layer is an insulating protective film. The rotor substrate and the stator substrate are mounted on the same axis, and the lower surface of the rotor substrate and the upper surface of the stator substrate are placed in parallel with each other, and the rotor electrode and the stator electrode face each other at a constant interval. A coupling capacitor is formed separated by δ.

In the second method for realizing the sensor, electrodes are arranged along the inner and outer column surfaces of a cylindrical body or a cylindrical ring. The rotor substrate uses a cylindrical body, and a bi-sinusoidal rotor electrode (the shape after spreading along the circumferential direction) formed by two vertically symmetrical sinusoids is arranged on the outer surface of the rotor substrate. The number of rotor electrodes is m, and the rotor electrodes are uniformly arranged on the peripheral surface, and the rotor electrodes are connected to each other by a conducting wire. The stator substrate uses a cylindrical ring, and its inner peripheral surface is covered with four layers of dielectric films, and the first layer is a metal film, which constitutes four excitation signal conductors. The second layer is an insulating film. The third layer is a metal film and constitutes a stator electrode, the shape of which is a curved rectangle (a rectangle extending along the circumferential direction), the same size, and between two adjacent electrodes A constant insulation interval is maintained, the number of stator electrodes is 4 m, and they are uniformly arranged on the peripheral surface. The fourth layer is an insulating protective film. The rotor substrate and the stator substrate are mounted on the same axis, and the rotor electrode and the stator electrode face each other, and are separated by a fixed interval δ to form a coupling capacitor.

  In the two types of structures described above, the number of rotor electrodes is m, the length is slightly shorter than the stator electrode, the width is the sum of the width of one electrode and one insulating interval, and two adjacent rotations. The distance between the child electrodes is three times the width of the rotor electrodes. Specifically, the shape of the rotor electrode is a combination of a region surrounded by a sine curve and an x axis in the [0, π] interval and a region surrounded by the sine curve and an x axis in a [π, 2π] interval. Configured. Therefore, it is possible to obtain a coupling capacitor that changes according to the sine rule with respect to the area, and to obtain an angular displacement modulation signal.

There are 4m stator electrodes, among which 4n + 1 (n = 0, 2, 3,..., M-1) electrodes are connected to one set to constitute an A excitation phase, and 4n + 2 electrodes are connected to one set. The B excitation phase is configured, and the fourth n + 3 electrodes are connected to one set to configure the C excitation phase, and the fourth n + 4 electrodes are connected to one set to configure the D excitation phase. The four excitation phases A, B, C and D of the stator are sequentially connected to sinusoidal excitation voltages Ua, Ub, Uc and Ud having an equal amplitude and equal frequency with a phase difference of 90 °, respectively, and one path on the rotor electrode. The traveling-wave signal Uo is generated, and the traveling-wave signal and the same frequency reference signal Ur fixed to the phase of one path are shaped by the shaping circuit and then compared in phase by the phase comparison circuit. The phase difference between the signals of both paths is displayed by the number of interpolated high-frequency clock pulses, and the angular displacement value of the rotor substrate relative to the stator substrate is obtained by scale conversion. As described above, the excitation voltage of the four paths and the same frequency reference signal Ur of the one path are given by the digital waveform synthesis technique.

The rotor substrate and the stator substrate rotate relatively, and the areas where the four excitation phases A, B, C, and D of the rotor electrode and the stator face each other are from nothing to small, from small to large, from large to small, and small. From time to time, the capacitance changes periodically, and the capacitance also changes accordingly. The A excitation phase electrode and the rotor electrode of the stator form a coupling capacitor C1, the B excitation phase electrode and the rotor electrode form a coupling capacitor C2, and the C excitation phase electrode and the rotor electrode form a coupling capacitor C3. The D excitation phase electrode and the rotor electrode form a coupling capacitor C4. The coupling capacitors C1, C2, C3, and C4 operate alternately two by two, and when two of the capacitors are operating, the other two capacitances are 0, and a traveling wave signal is generated on the rotor electrode. Uo is output. The traveling wave signal Uo and the same frequency reference signal Ur are shaped into a rectangular wave by a shaping circuit, and then phase-compared. The phase difference between the signals of both paths is displayed by the number of interpolated high-frequency clock pulses, and scale conversion. Thus, the angular displacement value of the rotor substrate relative to the stator substrate is obtained.

  The technical solution of the present invention directly forms an electric traveling wave by using electric field coupling based on a single circular multilayer structure, and combines the advantages of the conventional multi-grating displacement sensor.

  The present invention measures a single-circle coupled electric field constructed using a multi-layered stator, uses a single-circular sinusoidal sensor rotor electrode, directly induces an electric traveling wave, and calculates a displacement of a high-frequency clock pulse. The standard. Therefore, this sensor has the beneficial effects of low power consumption, high accuracy, simple structure, low required machine mounting accuracy, and high adaptability to industrial field environment.

FIG. 1A and FIG. 1B are schematic views of the first structure type of the present sensor, and the electrodes are arranged on the cylinder end faces of the stator substrate and the rotor substrate. FIGS. 2A and 2B are schematic views of the second structure type of the sensor, and the electrodes are arranged on the cylindrical column surfaces of the stator substrate and the rotor substrate. FIG. 3 is a positional relationship diagram of the electrodes on the stator substrate and the electrodes on the rotor substrate. FIG. 4 is a signal connection relation diagram of the stator electrodes. FIG. 5 is a schematic diagram of a coupling capacitor formed by a rotor electrode and a stator electrode. FIG. 6 is an electric circuit model principle diagram of the present invention. FIG. 7 is a block diagram of the signal processing principle of the present invention.

Hereinafter, the present invention will be further described with reference to the drawings.

As shown in FIG. 1A, FIG. 1B, FIG. 2A, FIG. 2B, and FIG. 3, the sensor according to the present invention includes both a rotor substrate 1 and a stator substrate 2. With parts. There are two types of embodiments in which a ceramic material is used as a substrate material and an electrode is formed by plating a layer of iron-nickel alloy on the ceramic surface.

Fig.1 (a) and FIG.1 (b) have shown the 1st structure. On the lower end surface of the cylindrical body of the rotor substrate 1, a total of 36 rotor electrodes 1-1 having the same size and shape are arranged at equal intervals along the circumferential direction, and the rotor electrodes extend along the circumferential direction. The shape after spreading is a bisinusoidal shape in which two sine curves are formed symmetrically vertically, and a conductor wire having a width of 1.8 mm connects the rotor electrodes to each other. The vertices are located on two circumferences having radii of 37.2 mm and 49 mm, respectively, and the maximum width position of each electrode has a corresponding central angle of 2.5 °. The upper end surface of the cylindrical body of the stator substrate is covered with a four-layer dielectric film, the first layer is a metal film, the second layer is an insulating film, the third layer is a metal film, and the fourth layer Is an insulating protective film. The metal film of the first layer constitutes an excitation signal conductor 2-2 that is four flat annular conductors, and the corresponding electrodes of the excitation phases of A, B, C, and D are connected to one set, respectively. The metal film of the layer constitutes a total of 144 stator electrodes 2-1 which are fan-shaped electrodes having the same radial height and the same central angle, and the inner ring radius of each electrode is 36.2 mm, The outer ring radius is 50 mm, the central angle is 2.4 °, and the insulation interval between adjacent electrodes is 0.1 °. The rotor substrate and the stator substrate are mounted on the same axis, and the lower end surface of the rotor substrate 1 and the upper end surface of the stator substrate 2 are opposed to each other in parallel. The rotor electrode 1-1 and the stator electrode 2-1 Are opposed to each other and are separated by an interval δ = 0.5 mm. The shape after spreading along the circumferential direction is a rectangle.

FIG. 2A and FIG. 2B show the second structure. On the outer surface of the cylindrical body of the rotor substrate 1, a total of 36 rotor electrodes 1-1 having the same size and shape are arranged at equal intervals along the circumferential direction, and the outer circle radius of the rotor substrate is 44.5 mm, the electrode has an upward height of 11.8 mm on the cylinder axis, each electrode has a central angle of 2.5 ° in the radial direction of the cylinder, and the rotating electrode extends along the circumferential direction. The expanded shape is a bisinusoidal shape in which two sine curves are vertically symmetrical, and a conductor wire having a width of 1.8 mm connects the rotor electrodes to each other. The inner surface of the cylindrical ring of the stator substrate is covered with a four-layer dielectric film, the first layer is a metal film, the second layer is an insulating film, the third layer is a metal film, and the fourth layer is It is an insulating protective film. The metal film of the first layer constitutes the excitation signal conducting wire 2-2 that is four annular conducting wires, and the corresponding electrodes of each excitation phase of A, B, C, and D are connected to one set, respectively. The metal films of the layers constitute a total of 144 stator electrodes 2-1, which are curved rectangular electrodes having the same height and the same width. The inner circle radius of the stator substrate is 45 mm, and the vertical axis of the cylinder axis of the electrodes is The height is 13.8 mm, the central angle of each electrode in the radial direction of the cylinder is 2.4 °, and the insulation interval between adjacent electrodes is 0.1 °. The rotor substrate and the stator substrate are mounted on the same axis, and the rotor electrode 1-1 and the stator electrode 2-1 face each other, and are separated by an interval δ = 0.5 mm.

In the above two embodiments, the length of the rotor electrode is slightly shorter than the length of the stator electrode, and the width is the sum of the width of one stator electrode and one insulating interval, and two adjacent rotors. The electrode spacing is the sum of the widths of the three stator electrodes. The first, fifth, ninth,..., 141 electrodes of the stator electrodes are connected to one set by one excitation signal conducting wire 2-2 to form an A excitation phase, and an excitation signal of Ua = Umsinωt is applied to the A excitation phase. Add. The second, sixth, tenth,..., 142 electrodes of the stator electrodes are connected to one set by one excitation signal conducting wire 2-2 to form a B excitation phase, and an excitation signal of Ub = Umcosωt is supplied to the B excitation phase. Add. The third, seventh, eleventh,..., And 143 electrodes of the stator electrode are connected to one set by one excitation signal conducting wire 2-2 to form a C excitation phase, and an excitation signal of Uc = −Umsinωt is provided in the C excitation phase. Add The fourth, eighth, twelfth,..., And 144 electrodes of the stator electrode are connected to one set by one excitation signal conducting wire 2-2 to form a D excitation phase, and the excitation signal of Ud = −Umcosωt is used as the D excitation phase. Add The peak value of the excitation signal is Um = 5 V, the frequency is f = 40 KHz, and the angular frequency is ω = 2πf = 8 × 10 ⁴ π.

As shown in FIGS. 5 and 6, the rotor electrode 1-1 and the A excitation phase electrode of the stator substrate form a coupling capacitor C1. The rotor electrode and the B excitation phase electrode of the stator substrate form a coupling capacitor C2. The rotor electrode and the C excitation phase electrode of the stator substrate form a coupling capacitor C3. The rotor electrode and the D excitation phase electrode of the stator substrate form a coupling capacitor C4. When the rotor substrate 1 rotates clockwise, the relative area of the C1 capacitor changes from large to small, and the relative area of the C2 capacitor changes from small to large. After rotating by an angle corresponding to one rotor electrode, the relative area of the C1 capacitor becomes zero, the relative area of the C2 capacitor starts to change from large to small, and the relative area of the C3 capacitor is small. It begins to turn big. After further rotation by an angle corresponding to one rotor electrode, the relative coverage area of the C2 capacitor becomes zero, the relative area of the C3 capacitor begins to change from large to small, and the relative coverage of the C4 capacitor Changes from small to large. After rotating again by an angle corresponding to one rotor electrode, the relative area of the C3 capacitor becomes zero, the relative area of the C4 capacitor starts to change from large to small, and the relative area of the C1 capacitor is small. Will change greatly. When the rotation for one machine cycle is completed in this way, the capacitances of C1, C2, C3, and C4 also exhibit periodic changes correspondingly. The rotor electrode outputs a traveling wave Uo, and the fundamental wave equation is expressed as follows.
Uo = KeUMsin (ω + πx / W) (1)
Here, Ke is an electric field coupling coefficient, x is a relative angular displacement between the rotor and the stator, and W is four times the angle corresponding to the rotor electrode.

As shown in FIG. 7, the induced sine traveling wave signal Uo and the same frequency reference sine signal Ur fixed to the phase of one path enter the shaping circuit and are converted into two rectangular wave signals of the same frequency. After that, it is sent to the phase comparison circuit for processing. After obtaining the phase difference between the signals of the two paths using a high-frequency clock interpolation technique and performing calculation processing, an angular displacement value between the rotor substrate and the stator substrate of the sensor can be obtained.

Claims (7)

An electric field type time grating angular displacement sensor comprising both a rotor and a stator,
The rotor has a number m of rotor electrodes (1-1) and is arranged at equal intervals over the entire annular surface of the rotor substrate (1);
The stator has a quantity of stator electrodes (2-1) of 4 m, and is arranged uniformly on the entire annular surface of the stator substrate (2), m is an integer of 1 or more,
The fourth n + 1 electrodes of the stator electrode are connected to one set to constitute an A excitation phase, the fourth n + 2 electrode of the stator electrode is connected to one set to constitute a B excitation phase, and the fourth n + 3 electrode of the stator electrode Are connected to one set to form a C excitation phase, and the fourth n + 4 electrodes of the stator electrodes are connected to one set to form a D excitation phase, and n = 0, 1, 2, 3,..., M−1. Yes,
The four excitation phases A, B, C and D of the stator are sequentially connected to sinusoidal excitation voltages Ua, Ub, Uc and Ud of equal amplitude and equal frequency with a phase difference of 90 °, respectively.
The rotor substrate and the stator substrate are mounted on the same axis, and the rotor electrode (1-1) and the stator electrode (2-1) face each other, and are separated by a fixed interval δ to form a coupling capacitor. Forming,
The rotor substrate and the stator substrate rotate relatively to generate a traveling wave signal Uo of one path on the rotor electrode, and the traveling wave signal and the reference signal Ur of the same frequency of one path are generated by a shaping circuit. After being shaped, the phase is compared by the phase comparison circuit,
The phase difference between the signals of both paths is displayed by the number of interpolated high-frequency clock pulses, and the angular displacement value of the rotor substrate with respect to the stator substrate is obtained by scale conversion.
An electric field time grating angular displacement sensor. The stator electrodes (2-1) are fan-shaped or curved rectangles, have the same size, and maintain a constant insulation interval between two adjacent electrodes.
The electric field time grating angular displacement sensor according to claim 1. The rotor electrode (1-1) is a bisinusoidal shape in which two sine curves are formed so as to be opposed to each other up and down after being arranged and developed along the circumferential direction, and the adjacent rotor electrodes (1-1) are connected by a conductive wire, the length of the rotor electrode is slightly shorter than the length of the stator electrode, and the width is the sum of the width of one stator electrode and one insulating interval. And the interval between two adjacent rotor electrodes is three times the width of the rotor electrodes.
The electric field time grating angular displacement sensor according to claim 1. The shape of the rotor electrode (1-1) is a combination of the sine curve and the region surrounded by the x axis in the [0, π] interval, and the region surrounded by the x axis and the sine curve in the [π, 2π] interval. Composed of
The electric field time grating angular displacement sensor according to any one of claims 1 to 3. The surface of the stator substrate is covered with a four-layer dielectric film, and the first layer is a metal film, which constitutes four excitation signal conductors (2-2), respectively A, B, C, D The stator electrodes corresponding to each excitation phase of
The second layer is an insulating film,
The third layer is a metal film and constitutes the stator electrode (2-1),
The fourth layer is an insulating protective film.
The electric field time grating angular displacement sensor according to any one of claims 1 to 3. The rotor substrate (1) and the stator substrate (2) are columnar bodies or cylindrical rings, and electrodes are arranged along the upper and lower end surfaces of the columns or the inner and outer column surfaces of the cylindrical ring.
The electric field time grating angular displacement sensor according to any one of claims 1 to 3. The A excitation phase and the rotor electrode (1-1) of the stator electrode (2-1) form a coupling capacitor C1, and the B excitation phase and the rotor electrode form a coupling capacitor C2. C excitation phase and the rotor electrode form a coupling capacitor C3, D excitation phase and the rotor electrode form a coupling capacitor C4,
The capacitors C1, C2, C3, and C4 that circulate and change alternately operate two by two to form a coupling path of alternating electric fields, and the rotor electrode outputs a traveling wave signal Uo.
The electric field time grating angular displacement sensor according to any one of claims 1 to 3.

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